IE 9 Release Candidate Now Available

This feature-complete, final test version of Microsoft's newest browser can now be downloaded from Microsoft's showcase site here. It was previously available as a beta. Those who already use the IE 9 beta will get an automatic update to the RC version, according to Microsoft's announcement today. When the browser is released to the Web as a final product, RC users similarly will get an automatic update to the latest build.

Typically, Microsoft doesn't add too many new features with an RC, but this IE 9 release appears to be an exception. The beta already demonstrated a marked departure from IE 8. Its streamlined user interface and speed improvements represent a new shot at competing browsers.

Microsoft poured a tremendous amount of engineering work and marketing promotion in creating IE 9, based mostly on emerging HTML 5 standards and a "write once, run anywhere" philosophy for Web sites. The aim is to help Web developers avoid having to code for perceived quirks in the browser, as was standard operating procedure for IE 6.

The new browser likely will do much to shore up the monthly percentage-point market losses Microsoft has had with IE 8, which still leads in use over other browsers with a 34.2 percent market share, according to January Net Applications data.

The one new feature projected by Microsoft, and now included in the IE 9 RC, is the browser's "tracking protection" feature. Users can ward off unwanted third-party tracking of their Web surfing behavior by selecting lists of URLs. The URL lists also indicate permitted tracking, if wanted. Microsoft is bringing this concept to the Worldwide Web Consortium (W3C) for standardization, according to a blog post by Dean Hachamovitch, corporate vice president of Internet Explorer. A few third parties are already offering tracking protection lists, including Abine, EasyList, PrivacyChoice and TrustE.

Microsoft also included an ActiveX filter in the RC, which lets users control which sites can use Microsoft's ActiveX technology with IE 9 -- a common security consideration. The download manager in IE 9 has an improved user interface and warns users when a download might be sketchy or potentially harmful to a user's system. The InPrivate browsing feature, which doesn't record histories and cookie tracking during a browsing session, now works with pinned sites.

Pinned sites are created by dragging a Web site's icon next to the address bar (called the "One Box" in IE 9) to the task bar of IE 9, which is typically located at the bottom of the browser. This feature, which isn't new in the RC, allows users to quickly access their favorite sites. Microsoft designed this feature so that Web developers can associate jump lists (a list of links) with those pinned sites. The pinned sites feature is improved in the RC by allowing sites to be pinned to vertical task bars; additionally, users can specify multiple home pages in a pinned site.

Another UI improvement in the IE 9 RC is the ability to create a separate row for multiple tabs. These tabs can be closed by hovering the mouse cursor over them, rather than by having to click on them first. Hachamovitch stated in Microsoft's announcement that most people browse with just five tabs or less running in their browsers, but the team responded to user feedback and added this feature anyway. Microsoft considered 17,000 requests from IE 9 testers to create the RC build, Hachamovitch stated.

Microsoft has tuned up IE 9's performance with the RC. Ryan Gavin, Microsoft's senior director of Internet Explorer, cited a 35 percent speed improvement over the beta on the WebKit SunSpider test, according to a blog post.

Microsoft tends to downplay such benchmark performance tests, while also citing them. Instead, the IE team produces HTML 5 test cases, which are submitted to the W3C. Browser results running those tests are shown at Microsoft's test drive portal. Microsoft reserves its HTML5 Labs site for developing HTML 5 standards considered promising but not ready for prime time.

A table of test results, reproduced in Microsoft's announcement, shows varying test results for the top competing browsers (Firefox, Opera, Safari and Chrome), while the IE 9 RC had scores of 100 percent. All told, Microsoft has submitted "just under 4000 test cases" to W3C Working Groups. The tests represent interpretations by the Microsoft team of the HTML 5 specs under consideration.

Finally, Microsoft added a few new features of interest to Web developers, including HTML 5 geolocation, CSS 3 two-dimensional transforms and HTML 5 semantic elements. The canvas element now can use the globalCompositeOperation property in IE 9 and Microsoft boosted CanvasPixelArray performance.